Process of making carbonblack



Tatented' Dec. 1131, 11023.

UNTTEID? STATES lhdtdfillil PATENT FFT@E JAMEQ W. M'IIN, JR, OF CLENDENIN, WEST VIRGINIA, ASSIGWOR TO CARBIDE AND CARBON CHEMICALS CORPORATION, A CORPORATION OF NEW YORK.

1912061388 OF MAKING CABIBONBLACK.

Ito Drawing.

To all whom it ma concern:

Be it known that ,JAMEs W. MARTIN, Jr, a citizen of the United States residing at Clendenin in the county of Kanawha and State of West Virginia, have invented certain new and useful Improvements in Processes of Making Carhonblack, of which the following is a specification.

The invention is a process of manufacturing carbon-black by the arrested combustion of hydrocarbons or mixtures thereof.

Carbon-black is extensively manufactured by burning natural gas in such a way that the carbon of the hydrocarbon. molecules is not completely burned to gaseous products, the unburned carbon being deposited as a soot useful as a pigment and for other purposes. In such processes, combustion is arrested, as by brin 'ng into theflame surfaces maintained at a Tdw enough temperature to cool the products of combustion at an intermediate stage of the oxidizing reactions.

Burners and collecting surfaces of the widest variety have been proposed and used, but it has not been found possible to increase the yield of black above a certain maximum, nor to increase the tinctorial power of the product beyond certain limits.

By the method of my invention, it is possible to produce from a given amount of material, a much larger amount of black than was obtainable by the process heretofore employed. The quality of the black thus produced is fully as good as the prior product and in many instances my product is of higher quality than the blacks now regarded as standard.

This improved result is obtained by preheating the gaseous hydrocarbon material before passing it to the burner. The optimum preheating temperature varies somewhat with difierent raw materials. In the case of a natural 1- as such as that largely employed in the est Virginia field for making carbon-black, a preheating tempsi'lature of about 400 C. is preferred.

en the temperature to which the gas is preheated is below about 200 0., there is no important increase in the yield of carhon-black. With preheating temperatures between about 200 C. and about 300 (1., there is a measurably increased yield. Above 300 (1., the yield increases quite rapidl with the preheating temperature. Such hydrocarbon gases as have been in- Applieatton filed February 1, 1923. serial 180. 610,440.

vesti gated also show a limit which the preheating temperature should not exceed, be cause of the decomposition of the gas with deposition of carbon within the burner which results from excessive overheating. With some hydrocarbon mixtures the upper limit of preheating, fixed by this consideration, is as low as 500 C.

It is well known that gas is perceptibly preheated in its passage through burners of very many types, heat being conveyed from the flame to the burner, and thence to the gas within the burner by radiation or conduction, or even by convection. So far as I am aware, the amount of preheating which can take place in any burner heretofore used or proposed for the manufacture of carbon-black is entirely inadequate to give the advantageous efl'ects obtainable with my invention.

The burners and other apparatus now employed are well adapted for use in connection with my process, and no complicated or expensive additions are required. It is sufficient merely to pass the gas, on its way to the burners, in such proximity to the flames, and for such a time, that it attains the desired temperature before reaehin the burners. It is then burned and the lack collected in accordance with any usual practice.

The process is applicable not only to natural gas but to fractions and'concentrates therefrom, to other mixtures of gaseous hydrocarbons, and to single hydrocarbons such as ethane, propane, or butane as well.

In a particular instance, a material capable of giving only 0.7 ep'ound of black per thousand cubic feet when not preheated, gave by my process 4.0 pounds of black per thousand cubic feet, the procedure remaining unchanged except for the provision of a reheating step.

his application is a continuation in part of the copending a plication Serial No. 596,871, filed by me ct. 25, 1922.

I claim:

1. Process of making carbon black from hydrocarbon material aeriform under normal conditions of temperature and pressure, which comprises preheating said material to a temperature above 200 C. and then burning the material under conditions adapted to form carbon black.

2. Process of mal n'ng carbon black from a, gas mixture consisting of hydrocarbons comprises preheating the gas to a temperanormally present in natural gas, which comture between 200 (J. and 500 (1., and then i prises preheating said hydrocarbons to a, burning the gas under conditions adapted temperature in excess of 200 C. and then to form carbon black.

5 burning them under conditions adapted to 4. Process according to claim 3 in which form carbon black. the preheating temperature is about 400 C.

3. Process of making carbon black from In testimony whereof, ll afiix my signature.

natural gas of normal composition, which JAMES W. MARTIN, JR. 

